ns19.o-net.com.ua has no MX records.
Question and response
Question
dig ns19.o-net.com.ua. MX
Answer
The response has no answer records.
Authority
o-net.com.ua. 900 SOA ns19.o-net.com.ua. hostmaster.o-net.com.ua. 2025033003 600 1800 3600000 900
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0